AC is leaking from the coil – HVAC Troubleshooting in San Diego
Water dripping from the indoor evaporator coil is one of the most common calls we get in San Diego — and in most cases it’s condensate that has nowhere to go, not refrigerant. Once the source is identified, the fix is usually straightforward.
Your AC pulls humidity out of the air; that moisture collects on the cold coil, drips into a pan, and drains away. Anything that blocks that path sends water onto the floor instead.
Common reasons the coil leaks water
- A clogged condensate drain line — algae and slime build up and the pan overflows. This is the single most common cause.
- A cracked or rusted-through drain pan beneath the coil.
- A dirty filter that froze the coil; when the ice melts it overruns the pan.
- Low refrigerant, which also freezes the coil and then leaks as it thaws.
- A unit that isn’t level, or a drain line that has worked loose or lacks proper slope.
- A failed condensate pump on systems that pump water up and out.
Water or refrigerant?
Clear water points to a drainage problem. An oily film, a faint hissing, ice on the lines, or weak cooling alongside the leak can instead mean a refrigerant leak — that’s a sealed-system repair and not a DIY job. The two are fixed very differently, which is why an accurate diagnosis matters.
What to do right now
- Turn the system off at the thermostat to stop more water and protect your floors and ceiling.
- Replace a dirty air filter.
- Mop up standing water and check the drain pan.
- Don’t pour chemicals blindly into the drain — call for an inspection so the real cause is cleared.
How we prevent it from coming back
We clear and flush the condensate line, confirm the pan and slope, check the filter and coil, and verify the refrigerant charge so the coil isn’t freezing. Annual maintenance keeps the drain clear — the cheapest insurance against water damage.
If your AC is leaking from the coil in San Diego, Prime Air Solutions will clear the drain, repair the pan, or locate the refrigerant leak. Call (619) 759-5111.
Frequently Asked Questions
Is the water leaking from my AC dangerous?
The water itself is condensation, but left unchecked it can damage drywall, flooring and promote mold. Shut the system off and have the drain cleared promptly.
Why does my AC leak water only sometimes?
Intermittent leaks often mean a partially clogged drain or a coil that freezes and thaws — it overflows when ice melts or when humidity is high and the line can’t keep up.
Can a dirty filter cause a water leak?
Yes. A clogged filter starves airflow, the coil freezes, and the melting ice overwhelms the drain pan. Changing the filter regularly prevents it.
How do I know if it’s refrigerant instead of water?
Refrigerant leaks usually come with weak cooling, hissing, ice on the copper lines, and sometimes an oily residue — not a puddle of clear water. A gauge test confirms it.
How can I stop the coil from leaking again?
Annual maintenance that flushes the condensate line, checks the pan and slope, and verifies the refrigerant charge is the most reliable prevention.